VNU Journal o f Scicucc. M athcinutics - Physics 24 (2008) 89-96

Wavelength shift in inicrosphere lasers
Tran Thi Tam^ % D ang Quoc Trung-, Trail A uh Vu“, Le H uu Minh^, Do N goc C hung“
I'a m llv o f H ngineenng Physics and Nano-Technolo
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Journal o f Science, M athematics - Physics 24 (2008) 89-96

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o f the m iư o r and could n o t give reasonable ex p lanation on q u e n c h in g o f som e m odes observed. The
coupling o f the T M m odes (electric field norm al to th e su rface) w ith th e surface w aves o f the m etal
plane m ay lead to th e ir quenching.
T he w id th o f the laser m ode is narrow er th a n ou r e x p e rim e n t’s eq u ip m en t resolution, so we do
not investigate its behavior.

4. Conclusions
The m icrosphere W G M lasers w as realized in E i^+ /Y b ^+ co -d o p ed p h o sp h ate glass using
9 7 6 n m pum p, to take full advantage o f energy tra n sfe r effect from ion Y tterb iu m to ion Erbium .
The coupling w as earn ed out b y fiber h a lf tap er te ch n iq u e in tw o sch em es, both gave good results.
The single laser line p o w e r m ay reach 1 5 0 n iy w ith only 2 b m W to tal p u m p pow er, and laser range


96

Tran Thi Tam et al. / IW U Journal o f Science, Mathematics - Physics 24 (2008) 89-96

extends from Ì5 3 2 .2 n rn to 1618.972m. T he red shift ciTcct, w hich associated w ith the th cn n al ef­
fect occuư cd insider sphere took place u n d er strong pum p. We have experim entally observed only a
em issio n w a v e le n g th s h ift b y ab out 0 .2 n m to the shorter sid e (b lu e { sh ift) w h ile v a n i n s the d istan ce

sphcrc-m iư or from lO O ^m ( ~ D) to IQf nn ( ~ O.ID). T he proposed red shift have not been confirm ed.
A ck n o w led g em en ts.

T h is w ork is supported b y a N ational B asic R esearch Program K T-04.

The

authors thank CN R -IFA C , N cllo C arrara Institute o f A pplied Physics, 50127 Firenze, Italy for supplyina
the Er^+ /Yh^+ co-doped p h o sphate elass.